Turf Playing Surface Aeration and Drainage System

ABSTRACT

A perforated pipe network beneath a playing surface. A blower connected to the pipe network drawing an air flow through the pipe network to create a vacuum. A drain pipe connecting to the pipe network. An air/water separator connected upstream of the blower for separating water from the air flow prior to entering the blower and channeling the water into the drain pipe for discharge. A flow control unit having a unit inlet connected to the drain pipe downstream of the air/water separator and a unit outlet discharging water to a drain outlet. The flow control unit blocking air flow through the unit inlet into the drain pipe when the blower is in the vacuum mode, and opening the unit inlet when a waterhead buildup at the unit inlet exceeds the vacuum level established by the blower to discharge water through the drain outlet.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from a provisional application filedMar. 17, 2005 under Ser. No. 60/662,913, and a non-provisionalapplication filed Mar. 31, 2005 under Ser. No. 11/094,995.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The present invention relates generally to subsurface aeration anddrainage systems, and more particularly, to a combination pressure andvacuum valve assembly for maintaining atmospheric isolation of thesubsurface system while separating water from air and draining the waterout of the system.

2) Description of Related Art

Subsurface systems have been developed for removing water and aeratingturf on sports fields and golf greens. A typical system is comprised ofa network of interconnected drainage pipe located beneath a region ofturf and a blower connected in such a manner that a partial vacuum ordifferential pressure can be created in the drainage network. Waterdrains from the network through one or more “outfall” pipes thattransport water to an external discharge location. For instance, manygreens have several ouffalls that are defined by the location ofdrainage pipes beneath the green. Greens with several surface gradessloping away from a ridge, for example, are often plumbed with anoutfall for each sloped region.

In the vacuum mode of operation, when water is removed as air is drawndown through a region of turf, water becomes entrained in the air streamand the mixture of air and water moves toward the blower. A devicecalled a “water separator” is normally located between the drain pipenetwork and the blower, and it functions to separate the air/watermixture into two separate streams comprising an air stream to the blowerand a water stream into the drainage outfall. There are several reasonswhy it is desirable to keep water from reaching the blowers. First,since the blowers are normally designed to move air, not heavy waterparticles, both efficiency and effectiveness are reduced whensignificant quantities of water become mixed in the air stream.Secondly, water tends to collect at low elevation regions or “saddles”in the pipes which reduces the effective cross section of pipe, therebyreducing air flow through the pipes and ultimately from the turf.

The blower system has a second mode of operation where pressure ratherthan a partial vacuum is applied beneath the green to cause air to flowup through the turf thereby aerating the root zone and moderatingtemperatures on the surface from the air stream that has been temperedby the substrate beneath the green.

In either the vacuum or the pressure mode, the pipe network beneath theregion being treated must be isolated from atmospheric pressure. Withoutsuch isolation, there would be little or no pressure differential andthe air path would tend to go between outfalls and the blower ratherthan through the turf to the blower.

Various forms of separators and valves have been developed to break theair-water mixture into two streams of flow and at the same time provideatmospheric isolation between the vacuum or pressure created by theblower and the discharge outfall. One such conventional separatorconsists of a barrel-chamber configured such that the water/air steamentering the chamber encounters a baffle that causes water to dropgravitationally to the bottom while air continues moving above the waterlevel to a port near the top of the chamber that is connected to theblower. An important feature of conventional separators is a “J trap”pipe configuration connected to the bottom of the barrel and throughwhich the water discharges from the barrel into the outfall pipe. The Jtrap serves to isolate the pressure or vacuum in the separator from theoutfall pipe. As water accumulates in the vault and in the J trapbeneath, it builds up enough pressure head to overcome the vacuumcreated by the blower at which point water flows out of the J trap,through the drain line to the discharge outfall. An example of such asystem can be found in U.S. Pat. No. 5,507,595.

Proper function of the J trap depends upon sufficient water being heldto counteract pressure or partial vacuums created by the blower in theseparator. If the system is in the pressure mode, for instance, and thepressure level is 20 inches Water Gage (WG), then the out leg of the “J”trap must be greater than 20 inches to counter the blower pressure. Inthe vacuum mode the longer down leg must be approximately 20 incheslonger than the outgoing leg in order to develop enough pressure topermit water to escape from the outgoing leg without filling theseparator barrel. When the two modes of operation are taken intoaccount, pressure and vacuum, the trap must be greater than 48 inchesdeep to properly isolate the blower vacuum pressure beneath the greenfrom the atmospheric pressure in the drain line. The overall depth ofthe excavation required to install and cover a separator plus a J trapis approximately eight (8) feet.

Normally only one outfall of a multiple-outfall drain network beneath agreen is connected through a separator to a blower. Additional ormultiple outfalls in the same network must also be isolated fromatmospheric pressure in order for the proper pressure or vacuum levelsto be established within the drain-pipe network beneath the turf.Conventionally, J traps are also used for this purpose, and a golf greenwith, for example, three ouffalls will typically employ three J trapswith one located on a separator unit and one on each of the remainingtwo outfalls.

However, there are several problems with this type of arrangement. Morespecifically, during installation, deep excavation is required toinstall a separator with J trap or a J trap on a multiple outfall green.Installation crews can lay pipe and make reliable connections much moreexpeditiously where deep excavations are not required. Deep excavationsrequire specialized equipment, such as back-hoes and the like, andequipment operators that are not needed for shallow trenching. The costand time of installation increases when deep excavations are required.

Further, with regards to reliability, J traps, by design, have deepcurved channels through which the water travels to the dischargeoutfall. These deep regions tend to collect sediment and becomeconstricted or clogged flow channels. J traps must be inspectedfrequently, especially after new green installations, where “fines” tendto wash out of the turf and settle in J traps. Another problem is causedwhen the surrounding soil shifts after a J trap is installed andconnected to a separator barrel. The relative displacement of the twotends to break or crack the J-trap fitting thereby permitting additionalsediment and fines to enter the trap or to render the J-trap inoperable.

Accordingly, it is an object of the present invention to provide a turfplaying surface aeration and drainage systems that does not require deepexcavation for installation and which maintains atmospheric isolation ofthe system while separating water from air and draining the water out ofthe system.

SUMMARY OF THE INVENTION

The above objective is accomplished according to an embodiment of thepresent invention by providing a turf playing surface aeration anddrainage system including a perforated pipe network installed beneaththe surface, and a blower operatively associated with the pipe networkfor establishing an air flow in the pipe network. A drain pipe isconnecting to the perforated pipe network for channeling water out ofthe pipe network. The blower has a vacuum mode in which the air flowcreates a vacuum in the pipe network. An air/water separator isconnected upstream of the blower for separating water from the air flowprior to entering the blower in the vacuum mode and channeling the waterinto the drain pipe for discharge through a drain outlet. A flow controlunit having a unit inlet is connected to the drain pipe downstream ofthe air/water separator and a unit outlet discharging water to the drainoutlet. The flow control unit has a vacuum mode of operation blockingair flow through the unit inlet into the drain pipe when the blower isin the vacuum mode, and opening the unit inlet in the vacuum mode when awaterhead buildup within the drain pipe at the unit inlet exceeds thevacuum level established by the blower at the air/water separator todischarge water through the drain outlet.

In a preferred embodiment of the invention, the flow control unitincludes a vacuum section having a first valve element movable between afirst position blocking air and water flow through the unit inlet in thevacuum mode, and a second position allowing discharge of water to thedrain outlet at a prescribed waterhead buildup. In a furtheradvantageous embodiment, the first valve element includes a flappercarried at the unit inlet for sealing off the unit inlet in the vacuummode and opening at a prescribed waterhead buildup level to dischargethe water through the unit outlet.

In a further embodiment, the blower may be constructed and arranged witha pressure mode of operation in which the air flow is directed into theperforated pipe network and up to the turf playing surface.Advantageously, the flow control unit includes a pressure section havinga second valve element movable to a first position in the pressure modeblocking the air flow through the unit outlet to prevent the air flowfrom exiting through the drain outlet, and the second valve elementmovable to a second position in the vacuum move allowing water to exitthrough the unit outlet. In a preferred embodiment, the second valveelement includes a float ball directed by the air flow in the pressuremode into the unit outlet to block air flow through the unit outlet, andwherein the float ball is caused to float out of the unit outlet duringthe vacuum mode by water entering the flow control unit to allow waterto exit through the unit outlet and be discharged through the drainoutlet.

In a further advantageous embodiment, a water bypass channel is includedin the unit outlet for discharging water to the drain outlet during thepressure mode when the second valve element is in the first position.

Further, the invention includes sloping the drain pipe downward from theair/water separator to position the flow control unit at a lowerelevation than the separator to promote water drainage to the drainoutlet and establish a prescribed waterhead buildup. In a preferredembodiment, the grade of slope of the drain pipe between the air/waterseparator and the flow control unit is generally between 5% and 40%depending on the length of the drain pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The construction designed to carry out the invention will hereinafter bedescribed, together with other features thereof. The invention will bemore readily understood from a reading of the following specificationand by reference to the accompanying drawings forming a part thereof,wherein an example of the invention is shown and wherein:

FIG. 1 is a plan view showing an aeration and drainage system for a turfplaying surface according to the present invention;

FIG. 2 is an enlarged view of a distributed air/water separator and flowcontrol unit according to the present invention;

FIG. 3 a is a detailed view of the flow control unit operating in avacuum mode creating a waterhead buildup according to the presentinvention;

FIG. 3 b is a detailed view of the flow control unit of FIG. 3 a in avacuum mode of operation in which the waterhead buildup is relievedaccording to the present invention; and,

FIG. 3 c is a detailed view of the flow control unit of FIG. 3 a in apressure mode of operation.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

With reference to the drawings, the invention will now be described inmore detail. Referring to FIG. 1, a turf playing surface, designatedgenerally as 10, is shown having an aeration and drainage system,designated generally as 12, for controlling water drainage from theplaying surface, as well as aerating the playing surface to promote turfgrowth and maintenance.

Aeration and drainage system 12 includes a fluid flow network,designated generally as 14, having a plurality of perforated pipes 16and a manifold pipe 17 installed beneath playing surface 10 throughwhich an air flow passes for aerating and removing water from theplaying surface. Fluid flow network 14 further includes a drain pipe 18for channeling the water to a drain outlet 20, which typically may emptythe water into a collection pond.

A blower 22 is operatively connected in fluid communication with fluidflow network 14 for creating an air flow 30 through the flow network,and in particular, through the perforated pipes, which may beselectively a vacuum air flow 30 a, or a pressure air flow 30 b. Blower22 has a vacuum mode of operation which draws air flow 30 a throughfluid flow network 14, which is then vented through an above ground vent24. Air flow 30 a creates a vacuum in fluid flow network 14 to draw airand water down through the playing surface and the perforated pipes toprovide a desired drainage or aeration effect on the turf playingsurface. In a further embodiment, blower 22 may be constructed andarranged with a pressure mode of operation in which air flow 30 a isreversed and pressure air flow 30 b is directed into fluid flow network14 where it exits out perforated pipes 16 and travels up to turf playingsurface 10, which is useful for aeration of the turf root system andtemperature control of the turf. Alternatively, the system can beconstructed and arranged to operate exclusively in a pressure mode, orexclusively in a vacuum mode and is not restricted to being operatablein both a vacuum and pressure mode, although the dual mode embodiment ismost advantageous.

As best shown in FIG. 2, an air/water separator 26 is connected to fluidflow network 14 upstream of blower 22 for separating water, designatedby reference arrow 28, from air flow 30 prior to the air flow enteringblower 22 in vacuum mode. The water is channeled into drain pipe 18 fordischarge through drain outlet 20, as is described in detail hereinbelow. Removing the water from the air flow to the blower reduces wearand tear on the blower components and results in a more efficient airflow in the system. When blower 22 is operating in pressure mode, airflow is directed down drain pipe 18 in addition to perforated pipes 16.In either vacuum or pressure mode, the air flow will travel through thepath of least resistance. Accordingly, if drain pipe 18 is open ended,when the blower draws a vacuum, it will simply suck air up drain pipe 18and vent it out vent 24, drawing very little if any air down through theperforated pipes. Also, in pressure mode, air will primarily exit outthe drain pipe if not controlled to direct the air up and out ofperforated pipes 16.

Advantageously, referring to FIG. 2, a flow control unit, designatedgenerally as 32, is provided to maintain atmospheric isolation of thefluid flow network by preventing air intake and exit through drain pipe18, while further allowing for the discharge of water through drainoutlet 20. Flow control unit 32 includes a unit inlet 34 connected todrain pipe 18 downstream of air/water separator 26. A unit outlet 36 isprovided for connection to additional drain pipe or to drain outlet 20for discharging water from drain pipe 18.

Referring to FIGS. 3 a and 3 b, flow control unit 32 has a vacuum modeof operation blocking air flow 30 a from drawing additional air inwardthrough unit inlet 34 into drain pipe 18 when blower 22 is operating invacuum mode. Unit inlet 34 only opens during vacuum mode operation whenwater 37 builds up to create a waterhead, designated generally as 38,within drain pipe 18 at unit inlet 34, best shown in FIG. 3 a. Once thewaterhead exceeds the force of the vacuum established by blower 22within the fluid flow network, and particularly at air/water separator26, flow control unit 32 open unit inlet 34 and water 37 passes throughthe control unit and is discharged through drain outlet 20, as bestshown in FIG. 3 b. After the waterhead buildup is relieved flow controlunit 32 closes unit inlet 34 to prevent air intake. Unit inlet 32 opensonly to the extend water forces it way through unit inlet 32 as a resultof the waterhead pressure on unit inlet 32. Accordingly, little to noair is able to enter the fluid flow network through unit inlet 32, whichthus maintains the vacuum established by blower 22.

In a preferred embodiment of the invention, flow control unit 32includes a vacuum section, designated generally as 40, having a firstvalve element 42 movable between a first position, designated generallyas 44 and shown in FIG. 3 a, closing off unit inlet 34 and blocking airand water flow through unit inlet 34 in vacuum mode. Referring to FIG. 3b, first valve element 42 further has a second position, designatedgenerally as 46, which opens inlet 34 allowing discharge of water to thedrain outlet at a prescribed waterhead buildup. Once waterhead buildup38 is partially relieved, the vacuum force of air flow 30 a will causefirst valve element 42 to close unit inlet 34 again in order to preventair intake up drain pipe 18 in an automatic manner as a result ofpressure differentials between fluid flow network 14 and the surroundingatmosphere. In a preferred embodiment, first valve element 42 includes aflapper, also designated 42, pivotally carried at unit inlet 34 forsealing off the unit inlet in the vacuum mode to create waterhead 38,and opening at a prescribed waterhead buildup level to discharge thewater through unit outlet 36. For maintenance purposes, a removable lid48 is carried by vacuum section 40 of flow control unit 32 to provideaccess for cleaning and maintenance.

In a further advantageous embodiment, referring to FIG. 3 c, flowcontrol unit 32 may also include a pressure section, designatedgenerally as 50. When blower 22 is operating in pressure mode, air flow30 b is directed down through drain pipe 18. To prevent the air flowfrom exiting, a second valve element 52 is provided which is movable toa first position, designated generally as 54, in the pressure mode whichblocks air flow 30 b for exiting through unit outlet 36 to prevent theair flow from exiting through drain outlet 20. Second valve element 52is also movable to a second position, designated generally as 56, shownin both FIGS. 3 a and 3 b. Second valve element 52 is moved to secondposition 56 in the vacuum mode of operation for blower 22 and flowcontrol unit 32 which allows water 37 to exit through unit outlet 36. Inthe illustrated embodiment, second valve element 52 includes a floatball, also designated 52. Float ball 52 is directed by the air flow inthe pressure mode into unit outlet 36 to block air flow through the unitoutlet. However, when blower 22 is switched to vacuum mode, float ballis caused to float out and away from of unit outlet 36 by water enteringthe flow control unit to allow the water to exit through unit outlet 36and be discharged through the drain outlet, as best shown in FIG. 3 b.For maintenance purposes, a removable lid 58 is carried by pressuresection 50 of flow control unit 32 to provide access for cleaning andmaintenance.

Referring to FIG. 3 c, in a further advantageous embodiment, a waterbypass channel 60 is included in the unit outlet for discharging waterto the drain outlet during the pressure mode when second valve element52 is in the first position 54 to block air flow from exiting unitoutlet 36. Because residual water may enter fluid flow network 14 duringpressure mode operation, it is advantageous to allow the water to drainfrom the system to prevent deposit buildup and other maintenance issues.However, when second valve element 52 is in first position 54, it blocksboth air and water from entering unit outlet 36. Accordingly, waterbypass channel 60 allows small amounts of water to be diverted aroundsecond valve element 52 for drainage, but does not allow a significantportion of air to exit in order to maintain pressure within fluid flownetwork 14.

Referring to FIGS. 1 and 2, drain pipe 18 is sloped downward from theair/water separator to position flow control unit 32 at a lowerelevation than air/water separator 26 to promote water drainage to drainoutlet 20 and establish a prescribed waterhead buildup in combinationwith first valve element 42. In a preferred embodiment, the grade,designated as reference angle A, of slope of drain pipe 18 betweenair/water separator 26 and flow control unit 32 is generally between 5%and 40% depending on the length of the drain pipe, as detailed in table1 below.

TABLE 1 Pipe length between air/water separator and flow control unit(for a blower generating 24 inch WG vacuum) Grade (% slope) Pipe length 5% 100 ft  10% 50 ft 20% 25 ft 30% 17 ft 40% 13 ft

Accordingly, aeration and drainage system 12 of the present inventionpreferably includes the combination of a vacuum section 40 and apressure section 50 each having a valve element 42, 52 that togetherselectively and automatically, without mechanical actuation, prevent thedischarge or intake of air flow and water into fluid flow network 14.This system eliminate the need for deep excavations, external controls,and is less prone to clogging than conventional drainage systems, suchas the “J” trap discussed above.

Vacuum section 40 may include a backwater or check valve that permitswater and air flow in one direction only. As discussed above, thepreferred embodiment employs a flapper 42 that opens in one directionwhen the air flow or water pressure from the source, drain pipe 18, isgreater than the pressure of the destination, drain outlet 20. Pressuredifferences cause the flapper to open and close without the aid ofsprings or other mechanical means.

With regards to pressure section 50, it may be constructed and arrangedas a “T” fitting containing a float ball 52 with unit outlet 36 having aprescribed opening such that in the pressure mode float ball 52 isconstrained by pressure of air, and in some instances water, to blockthe discharge opening. In the vacuum mode of operation for blower 22,water 37 entering the device causes the ball to float up and away fromthe opening, thereby enabling unrestricted flow of water through theunit outlet 36.

An important feature of second valve element 52 in pressure section 50is the size and shape of unit outlet 36. When float ball is used assecond valve element 52, it is pushed into the opening by thecombination of air and any standing water pressure behind it. The normalbuoyant pressure on float ball 52 is disrupted by the absence ofhydraulic pressure in the opening, and the ball has a tendency to becomelodged in the opening by the combination of air and water pressurebehind it. Therefore, the opening must be large enough to permit fullflow in the vacuum mode, yet small enough to reduce the tendency to getstuck from pressure differences in the pressure mode. In a preferredembodiment, using a ball of 5.9″ diameter, together with an opening forunit outlet 36 of 3″ in diameter provides sufficient buoyancy toovercome a pressure head of 9″ WG (Water Gage). Preferably, the centerline of the opening matches that of the ball to ensure the best ft.

Another consideration was the removal of water that may flow into thedrainage system while the system is in the pressure mode. As discussedabove, a small water bypass channel is therefore included in unit outlet36. It has been tested that a bypass opening of 0.5″ radius dischargeswater at sufficient rate to preclude backup in the pressure sectionwhile at the same time preventing significant air flow loss when nowater is present in flow control unit 32. Tests yielded bypass flowtypically less than 15% off the main flow.

When the two sections 40, 50 are connected in series, water and air canpass freely in one direction, but not the other. The two sections may belocated adjacent to each other or separated by an interconnectingsection of pipe. Alternatively, the sections may be formed together in asingle unit containing both first and second valve elements 42 and 52.

This dual valve system can be used in conjunction with appropriatedrainage piping to eliminate the traditional air/water separator and “J”trap configuration. This dual valve arrangement enables the constructionof a distributed air/water separator that makes use of the slope orgrade of the region between turf playing surface 10 and drain outlet 20to accumulate a waterhead sufficient to counteract the vacuum modenegative pressure to discharge water while under vacuum.

Essentially, the system is comprised of three functional sections thatare connected together in a relatively shallow trench running from theend of perforated pipes 16 toward drain outlet 20. Going from the turfplaying surface toward the drain outlet, the three sections are: 1)air/water separator 26, 2) drain pipe 18, and 3) flow control unit 32.

Air water separator 26 includes a “Y” shaped fitting oriented along thefall line (or down-slope) with one leg 61 oriented in a generallyvertical position. The vertical leg is connected to blower 22 by an airline 62, while the other leg 64 is connected to the perforated pipes 16at an upper inlet 66, and connected to drain pipe 18 at a lower outlet68.

Since a waterhead must be developed between air/water separator 26 andflow control unit 32, the length of pipe required depends upon the slopeof ground in which drain pipe 18 is installed, as set forth in table 1above. A steep grade requires less pipe and a shallow grade requiresmore to produce a prescribed waterhead buildup to overcome the vacuumpressure generated by a given blower.

Generally, for a SubAir 7.5 HP blower manufactured by SubAir, Inc., ofAiken, S.C., the vacuum level is in the range of 20 to 24 inches WG and,therefore, the elevation drop from air/water separator 26 to flowcontrol unit 32 must be greater than 24 inches. However, it is preferredthat 36 inches be provided in this case to ensure proper operation offlow control unit 32. For a SubAir Portable Air Force-1 blower unit, thevacuum level is up to 45 inches WG, and the corresponding recommendedelevation drop is 60 inches (5 feet).

In the pressure mode, pressure section 50 of flow control unit 32restricts air flow to a fraction of the total flow coming from blower22, yet it provides a small bypass 60 for water flow in case waterdrains from the playing surface while in the pressure mode.

The system of the present invention may also be used as a stand-alonedevice to isolate multiple drain outlets from atmospheric pressure,thereby enabling vacuum/pressure in the drainage pipes to be controlledby the blower. A turf playing surface, such as a golf green, may haveseveral drain outlets that are defined by the location of the drainagepipes (perforated pipes 16) beneath the green for a given slope on thegreen. Greens with several sloping grades away from a ridge, forinstance, are often plumbed having drainage pipes with a drain outletfor each sloping region. In such cases the system must be installed insuch a manner as to take the specific drainage configuration intoaccount. There are several possibilities, namely, a continuous,interconnected aeration and drainage system beneath the green where avacuum or pressure on one drain outlet causes vacuum and pressuresthroughout the entire pipe network. In this case, air/water separator 26and blower 22 may be connected to one of the drainage outlets 20 or evento a clean-out port provided for the system. Any other drain outletsneed to have a flow control unit 32 connected between the perforatedpipes 16 and the drain outlet location such that vacuum and pressurelevels generated by blower 22 are isolated from the atmospheresurrounding the fluid flow network as described herein.

While a preferred embodiment of the invention has been described usingspecific terms, such description is for illustrative purposes only, andit is to be understood that changes and variations may be made withoutdeparting from the spirit or scope of the following claims.

1-21. (canceled) 22-33. (canceled)
 34. A turf playing surface aerationand drainage system including a plurality of perforated pipes installedin a turf profile beneath a turf playing surface, at least one blower influid communication with said perforated pipes having a vacuum mode ofoperation for establishing an air flow to create a vacuum to draw awater-laden air flow downwardly through said turf profile and pipes, anda sloped drain pipe in fluid communication with said perforated pipesfor receiving water separated from said water-laden airflow, said systemcomprising: a distributed air/water separator arrangement disposed influid communication with said blower and perforated pipes including saidsloped drain pipe facilitating a flow of water through the drainpipewhile a flow of air is delivered to the blower; a flow control unit influid communication with said drain pipe having a closable unit inletand a closable unit outlet; said unit inlet being closed to block airflow in a first direction through said fluid control unit in said vacuummode of operation causing water from said water flow to back up at saidunit inlet and create water under pressure at said unit inlet, and saidunit inlet being open to discharge the water through said control unitin a second direction opposite to said first direction when said waterpressure reaches a predetermined level.
 35. The system of claim 37wherein said distributed air/water separator arrangement includes a pipefitting in fluid communication with said blower and perforated pipeshaving an upstanding leg for connection to said blower and anintersecting leg connected to one of a supply line on a high side ofsaid playing surface and said drain pipe on a low side of said playingsurface.
 36. The system of claim 38 wherein said control unit includes afirst valve for closing said unit inlet in said vacuum mode, said firstvalve opening at a prescribed water pressure for drainage through saidcontrol unit, and said first valve closing when water pressure dropsbelow said predetermined pressure.
 37. The system of claim 39 whereinsaid blower has a pressure mode of operation in which said air flow isdirected into said perforated pipes and up through the turf profile. 38.The system of claim 40 wherein said flow control unit includes a secondvalve having a closed position in said pressure mode blocking an airflow from said drain outlet through said control unit, and having anopen position in said vacuum mode allowing water to discharge throughsaid drain outlet.
 39. The system of claim 41 including a water bypasschannel in said unit outlet for discharging water which enters said flowcontrol unit in said pressure mode to said drain outlet when said secondvalve is in a closed position blocking through said unit outlet.
 40. Aturf playing surface aeration and drainage system including a pluralityof perforated pipes installed in a turf profile beneath a turf playingsurface, at least one blower in fluid communication with said perforatedpipes having a vacuum mode of operation for establishing an air flow tocreate a vacuum to draw air and water downwardly through said turfprofile and pipes, and a drain pipe in fluid communication with saidperforated pipes for receiving a flow of the water, said systemcomprising: a flow control unit in fluid communication with said drainpipe having a closable unit inlet and a closable unit outlet; said flowcontrol unit having a first position in said vacuum mode for blockingair flow in a first direction through said fluid control unit whilebacking up said water at said unit inlet when closed to create waterunder pressure at said unit inlet, and a second position for dischargingsaid water through said control unit and said unit outlet when saidwater pressure reaches a predetermined level.
 41. The apparatus of claim43 wherein said unit inlet includes an inlet valve and said unit outletincludes an outlet valve; and said control unit includes a blockingposition and an open position in said vacuum mode of operation, saidinlet valve being closed in said blocking position to block the flow ofwater through said unit inlet and control unit while water is allowed toback up in said drain pipe upstream of said unit inlet under pressure,and said inlet valve is open in said open position so that said water isallowed to flow through said unit inlet and control unit.
 42. Theapparatus of claim 44 wherein said first valve includes a flappercarried at said unit inlet for sealing off said unit inlet in saidvacuum mode and opening at a prescribed water buildup level to dischargethe water through said unit outlet.
 43. The apparatus of claim 43including at least one blower having a pressure mode of operation inwhich said airflow is directed into the perforated pipe network andupwardly though the turf profile.
 44. The apparatus of claim 46 whereinsaid flow control unit includes a pressure control section having afirst control position in said pressure mode blocking an air flowthrough said drain outlet, and a second control position in said vacuummode allowing water to exit through said unit outlet.
 45. The apparatusof claim 47 including a water bypass channel in said unit outlet fordischarging water through said drain outlet in said pressure mode insaid first control position.
 46. In a turf playing surface aeration anddrainage system including a plurality of perforated pipes installed in aturf profile beneath a turf playing surface, at least one blower influid communication with said perforated pipes having a vacuum mode ofoperation for establishing an air flow to create a vacuum to draw awater-laden air flow downwardly through said turf profile and pipes, anda drain pipe in fluid communication with said perforated pipes forreceiving water separated from said water-laden air flow, a flow controlunit comprising: a flow control unit having an enclosure with a closableunit inlet for connection with said drain pipe and a closable unitoutlet; said flow control unit having a closed inlet position in saidvacuum mode for blocking air flow through said fluid control unit whilebacking up water at said unit inlet to create water under pressure atsaid unit inlet, and an open inlet position for discharging said waterthrough said control unit when said water pressure reaches apredetermined level.
 47. The apparatus of claim 49 wherein said unitinlet includes an inlet valve and said unit outlet includes an outletvalve; and said control unit includes a blocking position and an openposition in said vacuum mode of operation, said inlet valve being closedin said blocking position to block the flow of water through said unitinlet and control unit while water is allowed to back up in said drainpipe upstream of said unit inlet, and said inlet valve is open in saidopen position so that said water is allowed to flow through said unitinlet and outlet upon reaching a prescribed pressure.
 48. The apparatusof claim 50 wherein said inlet valve includes a flapper carried at saidunit inlet for sealing off said unit inlet in said vacuum mode andopening at said prescribed pressure to discharge the water through saidunit outlet.
 49. The system of claim 49 wherein said blower has apressure mode of operation in which said air flow is directed into saidperforated pipes and up through the turf profile, said flow control unitincludes an outlet valve having a first control position in saidpressure mode blocking an airflow through said drain outlet, and asecond control position allowing water to exit through said unit outletin said vacuum mode.
 50. The apparatus of claim 49 wherein said unitinlet includes an inlet valve seat and said unit outlet includes anoutlet valve; and said control unit includes a blocking position and anopen position in said vacuum mode of operation, said inlet valve beingclosed in said blocking position to block the flow of water through saidunit inlet while water is allowed to back up in said drain pipe upstreamof said unit inlet, and said inlet valve seat is open in said openposition so that said water is allowed to flow through said unit inletand outlet upon reaching said prescribed pressure.
 51. A method foraerating turf and removing water from a turf profile of a turf playingsurface wherein a fluid flow network having perforated pipes isinstalled in the turf profile below the playing surface, and a slopeddrain pipe having a drain outlet is connected in fluid communication tothe flow network, comprising the steps of: establishing a vacuum in saidfluid flow network to create a flow of air and water downwardly from thesurface into said perforated pipes; drawing the air into the blower;facilitating flow of the water through said sloped drain pipe and saiddrain outlet; providing a fluid control unit in fluid communication withsaid sloped drain pipe having an enclosure with a closable unit inletconnected to said drain pipe and a closable unit outlet; blocking airflow through said control unit when said vacuum is established in saidperforated pipes; and allowing water from a flow of water to back up atsaid unit inlet and be released through said unit inlet and control unitwhen the pressure of water in said drain pipe exceeds the vacuum forceon said fluid flow network whereby said unit inlet is open to dischargewater through said unit outlet.
 52. The method of claim 54 including thestep of pressurizing said fluid flow network to force air through saidperforated pipes up to said turf profile.
 53. The method of claim 55including the step of blocking air flow out of said unit outlet tomaintain pressurization of said fluid flow network.